The present art in door locking devices is seriously lacking in its ability to resist forceful entry. This is true because people so inclined have learned of the inherent weaknesses of the present art.
Only one bolt is used in the prior art. There is no back-up provision for that bolt, increasing the possibility of a successful break-in upon its failure.
Locks of the present art are disposed within the door with the bolt employed through door edge to detent in door facing when closed. This practice provides for insufficient material (usually wood), remaining on either side of bolt and from detent, in door facing to inside edge of door facing, to resist a violent blow from a person's body or foot.
The most common type of lock of the present art is the self-latching type. With this lock, the bolt is spring biased to detent in door facing (closed), and is provided with a beveled forward end to facilitate closing. A plastic card or the like, slipped past door jam and pressed against said bevel, forces bolt back against biasing spring and out of detent.
These weaknesses are not applicable to the present invention as will become apparent.
The strength of a solid hardwood door is lost when just a small amount of wood is available to resist forceful entry.